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Thermal Radiation Effects on Heat and Mass Transfer of Magnetohydrodynamics Dusty Jeffrey Fluid past an Exponentially Stretching Sheet 热辐射对磁流体动力学Dusty Jeffrey流体通过指数拉伸薄板传热传质的影响
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1172
Siti Nur Haseela Izani, Anati Ali
{"title":"Thermal Radiation Effects on Heat and Mass Transfer of Magnetohydrodynamics Dusty Jeffrey Fluid past an Exponentially Stretching Sheet","authors":"Siti Nur Haseela Izani, Anati Ali","doi":"10.11113/MATEMATIKA.V35.N2.1172","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1172","url":null,"abstract":"The heat and mass transfer of steady magnetohydrodynamics of dusty Jeffrey fluid past an exponentially stretching sheet in the presence of thermal radiation have been investigated. The main purpose of this study is to conduct a detailed analysis of flow behaviour of suspended dust particles in non-Newtonian fluid. The governing equations hav been converted into dimensionless form, and then solved numerically via the Keller-box method. The expression of Sherwood number, Nusselt number and skin friction have been evaluated, and then displayed in tabular forms. Velocity, temperature and concentration profiles are presented graphically. It is observed that large value of dust particles mass concentration parameter has reduced the flow velocity significantly. Increase in radiation parameter enhances the temperature, whereas the increment in Schmidt number parameter reduces the concentration.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42603233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
On Estimate of Malaysian Mortality Rates Using Interpolation Methods 用插值法估计马来西亚的死亡率
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1169
Nur Irsalina Ah Khaliludin, Z. M. Khalid, H. A. Rahman
{"title":"On Estimate of Malaysian Mortality Rates Using Interpolation Methods","authors":"Nur Irsalina Ah Khaliludin, Z. M. Khalid, H. A. Rahman","doi":"10.11113/MATEMATIKA.V35.N2.1169","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1169","url":null,"abstract":"Life table is a table that shows mortality experience of a nation. However, in Malaysia, the information in this table is provided in the five-year age groups (abridged) instead of every one-year age. Hence, this study aims to estimate the one-year age mortality rates from the abridged mortality rates using several interpolation methods. We applied Kostaki method and the Akima spline method to five sets of Malaysian group mortality rates ranging from period of 2012 to 2016. The results were then compared with the one-year mortality rates. We found that the method by Akima is the best method for the Malaysian mortality experience as it gives the least minimum of sum of square errors. The method does not only provide a good fit but also, shows a smooth mortality curve.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41780686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Process Improvement on Domestic Wastewater Treatment Stabilization Ponds by Using Mathematical Optimization Approach 应用数学优化方法对生活污水处理稳定池进行工艺改进
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1157
S. Sunarsih, D. Sasongko, S. Sutrisno
{"title":"Process Improvement on Domestic Wastewater Treatment Stabilization Ponds by Using Mathematical Optimization Approach","authors":"S. Sunarsih, D. Sasongko, S. Sutrisno","doi":"10.11113/MATEMATIKA.V35.N2.1157","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1157","url":null,"abstract":"In this paper, a mathematical optimization approach is used to improve the pollutant degradation process on domestic wastewater treatment stabilization ponds. The optimized process in this research is the pumping process that was modelled as a mathematical optimization problem. By using data that was collected in Sewon wastewater treatment in Yogyakarta, Indonesia, the pumping process can be optimized and the optimal decision was determined that can be applied to operate this wastewater treatment pond.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44725298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Comparison of Semivariogram Models in Rain Gauge Network Design 雨量计网设计中半变差模型的比较
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1155
Mohd Khairul Bazli Mohd Aziz, F. Yusof, Zalina Mohd Daud, Z. Yusop, M. Kasno
{"title":"Comparison of Semivariogram Models in Rain Gauge Network Design","authors":"Mohd Khairul Bazli Mohd Aziz, F. Yusof, Zalina Mohd Daud, Z. Yusop, M. Kasno","doi":"10.11113/MATEMATIKA.V35.N2.1155","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1155","url":null,"abstract":"The well-known geostatistics method (variance-reduction method) is commonly used to determine the optimal rain gauge network. The main problem in geostatistics method to determine the best semivariogram model in order to be used in estimating the variance. An optimal choice of the semivariogram model is an important point for a good data evaluation process. Three different semivariogram models which are Spherical, Gaussian and Exponential are used and their performances are compared in this study. Cross validation technique is applied to compute the errors of the semivariograms. Rain-fall data for the period of 1975 – 2008 from the existing 84 rain gauge stations covering the state of Johor are used in this study. The result shows that the exponential model is the best semivariogram model and chosen to determine the optimal number and location of rain gauge station.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46581102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
On Some Graphs of Finite Metabelian Groups of Order Less Than 24 关于小于24阶有限亚生意人群的若干图
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1054
I. Gambo, N. Sarmin, S. Omer
{"title":"On Some Graphs of Finite Metabelian Groups of Order Less Than 24","authors":"I. Gambo, N. Sarmin, S. Omer","doi":"10.11113/MATEMATIKA.V35.N2.1054","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1054","url":null,"abstract":"In this work, a non-abelian metabelian group is represented by G while represents conjugacy class graph. Conjugacy class graph of a group is that graph associated with the conjugacy classes of the group. Its vertices are the non-central conjugacy classes of the group, and two distinct vertices are joined by an edge if their cardinalities are not coprime. A group is referred to as metabelian if there exits an abelian normal subgroup in which the factor group is also abelian. It has been proven earlier that 25 non-abelian metabelian groups which have order less than 24, which are considered in this work, exist. In this article, the conjugacy class graphs of non-abelian metabelian groups of order less than 24 are determined as well as examples of some finite groups associated to other graphs are given.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45565417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Modified Model-Selection Criteria in a Generalised Estimating Equation for Latent Class Regression Models 潜在类回归模型广义估计方程中模型选择准则的改进
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1175
J. Purnomo, Chih-Rung Chen, Guangping Huang
{"title":"A Modified Model-Selection Criteria in a Generalised Estimating Equation for Latent Class Regression Models","authors":"J. Purnomo, Chih-Rung Chen, Guangping Huang","doi":"10.11113/MATEMATIKA.V35.N2.1175","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1175","url":null,"abstract":"In recent years, generalised estimating equations (GEEs) have played an important role in many fields of research, such as biomedicine. In this paper, we use GEEs for latent class regression (LCR) with covariate effects on underlying and measured variables. However, there are only a few model-selection criteria in GEEs. The widely known Akaike information criterion (AIC) cannot be used directly, since AIC is a full likelihood-based model, whereas GEEs are nonlikelihood based. Hence, we propose a modification to AIC in GEEs for (LCR) models, where the likelihood is replaced by quasi-likelihood, and a proper adjustment is made by giving a penalty term. The data of the modified hospital elder life program (mHELP) project are used to illustrate our method.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48852849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Fast and Robust Parameter Estimation in the Application of Fuzzy Logistic Equations in Population Growth 模糊Logistic方程在人口增长中的快速鲁棒参数估计
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1164
N. Izzah, Y. Hoe, N. Maan
{"title":"Fast and Robust Parameter Estimation in the Application of Fuzzy Logistic Equations in Population Growth","authors":"N. Izzah, Y. Hoe, N. Maan","doi":"10.11113/MATEMATIKA.V35.N2.1164","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1164","url":null,"abstract":"In this paper, extended Runge-Kutta fourth order method for directly solving the fuzzy logistic problem is presented. The extended Runge-Kutta method has lower number of function evaluations, compared with the classical Runge-Kutta method. The numerical robustness of the method in parameter estimation is enhanced via error minimization in predicting growth rate and carrying capacity. The results of fuzzy logistic model with the estimated parameters have been compared with population growth data in Malaysia, which indicate that this method is more accurate that the data population. Numerical example is given to illustrate the efficiency of the proposed model. It is concluded that robust parameter estimation technique is efficient in modelling population growth.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43611492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
g-Jitter Free Convection Flow of Nanofluid in The Three-Dimensional Stagnation Point Region 三维驻点区域纳米流体的g-抖动自由对流流动
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1116
M. Kamal, Anati Ali, S. Shafie
{"title":"g-Jitter Free Convection Flow of Nanofluid in The Three-Dimensional Stagnation Point Region","authors":"M. Kamal, Anati Ali, S. Shafie","doi":"10.11113/MATEMATIKA.V35.N2.1116","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1116","url":null,"abstract":"The three dimensional free convection boundary layer flow near a stagnation point region is embedded in viscous nanofluid with the effect of g-jitter is studied in this paper. Copper (Cu) and aluminium oxide (Al2O3) types of water base nanofluid are cho- sen with the constant Prandtl number, Pr=6.2. Based on Tiwari-Das nanofluid model, the boundary layer equation used is converted into a non-dimensional form by adopting non- dimensional variables and is solved numerically by engaging an implicit finite-difference scheme known as Keller-box method. Behaviors of fluid flow such as skin friction and Nusset number are studied by the controlled parameters including oscillation frequency, amplitude of gravity modulation and nanoparticles volume fraction. The reduced skin friction and Nusset number are presented graphically and discussed for different values of principal curvatures ratio at the nodal point. The numerical results shows that, in- crement occurs in the values of Nusset number with the presence of solid nanoparticles together with the values of the skin friction. It is worth mentioning that for the plane stagnation point there is an absence of reduced skin friction along the y-direction where as for axisymmetric stagnation point, the reduced skin friction for both directions are the same. As nanoparticles volume fraction increased, the skin friction increased as well as the Nusset number. The results, indicated that skin frictions of copper are found higher than aluminium oxide.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42623234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Conformable Fractional Partial Differentiation on n-Dimensional Time Scales n维时间尺度上的保形分数偏微分
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1075
Nazlı Yazıcı Gözütok, Uğur Gözütok
{"title":"Conformable Fractional Partial Differentiation on n-Dimensional Time Scales","authors":"Nazlı Yazıcı Gözütok, Uğur Gözütok","doi":"10.11113/MATEMATIKA.V35.N2.1075","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1075","url":null,"abstract":"In this study, the notion of a conformable partial differentiation of order alpha on time scales is introduced. Some properties of this new concept are given and relation between the conformable partial differentiation on time scales and the classical partial delta differentiation is revealed.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48965010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hartmann and Reynolds Numbers Effects in the Newtonian Blood Flow of a Bifurcated Artery with an Overlapping Stenosis 重叠狭窄的分叉动脉牛顿血流中的哈特曼和雷诺数效应
IF 0.4
Matematika Pub Date : 2019-07-31 DOI: 10.11113/MATEMATIKA.V35.N2.1177
Norliza Mohd Zain, Z. Ismail
{"title":"Hartmann and Reynolds Numbers Effects in the Newtonian Blood Flow of a Bifurcated Artery with an Overlapping Stenosis","authors":"Norliza Mohd Zain, Z. Ismail","doi":"10.11113/MATEMATIKA.V35.N2.1177","DOIUrl":"https://doi.org/10.11113/MATEMATIKA.V35.N2.1177","url":null,"abstract":"Abstract Blood flow through a bifurcated artery with the presence of an overlapping stenosis located at parent’s arterial lumen under the action of a uniform external magnetic field is studied in this paper. Blood is treated as an electrically conducting fluid which exhibits the Magnetohydrodynamics principle and it is characterized by a Newtonian fluid model. The governing equations are discretized using a stabilization technique of finite element known as Galerkin least-squares. The maximum velocity and pressure drop evaluated in this present study are compared with the results found in previous literature and COMSOL Multiphysics. The solutions found in a satisfactory agreement, thus verify the source code is working properly. The effects of dimensionless parameters of Hartmann and Reynolds numbers in the fluid’s velocity and pressure are examined in details with further scientific discussions.","PeriodicalId":43733,"journal":{"name":"Matematika","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43893598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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